DWISE1'S CREATION / EVOLUTION PAGE:
Earth's Rotation is Slowing


HARD HAT AREA

WATCH YOUR STEP


CAVEAT:

2017 September 13

I have finished rewriting this page except for the final section, Doing the Math".

I believe that I have addressed all the issues raised. All that is now left is to perform the analysis and comparisons of the various rates for the slowing down of the earth's rotation.

2017 June 28

I am in the process of rewriting this page.

A creationist correctly pointed out that I had made a misinterpretation (emphasis added):
Creationists claim that it's slowing down by one second per day every 12 to 18 months; ie, that after 12 or 18 months, the day will be one second longer.
I have rewritten that as:
Creationists claim that it's slowing down by one second every 12 to 18 months, thus requiring the addition of a leap second to compensate for that "lost second." That would translate to each day becoming longer by 1.8 to 2.7 milliseconds, which would amount to a full second in 12 to 18 months.
Actually, I feel that that is still a bit sketchy. I need to work through the math more rigorously in order to determine just what the claimed rates would mean for the length of a day at the end of that time period. My rewrite will include those calculations so that we can directly compare the claimed rates and their consequences with the actual rate and its consequences.

The refutation of this claim is still valid, though the factors that they are off by need to be nailed down with more rigorous math. The fact still remains that the rates in the creationist claims are grossly over-inflated, which leads to their ludicrous conclusions. And the nature of their mistake that led to those grossly over-inflated rates remains the same.

All that remains to be done is to crunch the numbers so that we can see just how far off they are. The main difficulty there is that we have no idea what kind of calculations the creationists had performed, if any. We don't know just how they had arrived at their conclusions nor how they had interpreted their rates. At best, I would need to reconstruct how those rates should be interpreted and ultimately how those rates would translate to the lengthening of the day over time. That is not a simple task.

I should point out that of the five examples of this claim that I quote, only two of them give any actual value for the rate of the slowing of earth's rotation; all that the other three ever say is that the earth's rotation is slowing down and then hand-wave their conclusions without saying anything about how those conclusions were arrived at. Even the original claim by Walter Brown (1979), which does give a rate ("almost one second a year"), ends up resorting to pure hand-waving to arrive at his conclusions.

It is only the fifth of five versions of the claim, Kent Hovind's extended claim from his seminar videos (2007, transcribed in 2013), which gives both a rate and a predicted effect derived from calculations involving that rate. His claimed rate is: "[The earth's rotation] is actually slowing down 1000th of a second everyday." Therefore, after 1,000 days (about three years) the day would be one second longer. Since I was able to use that rate to reproduce his predicted effect (day length of about 23.5 hours 6,000 years ago), I verified that that is what he is saying. That agrees with my misinterpretation, "after 12 or 18 months, the day will be one second longer", though Hovind's rate would require twice as long.

I now feel quite confident that Hovind's claim was the source of my misstatement. Creationist claims and arguments are very confused and it is difficult to keep from becoming confused yourself when you try to follow their logic. And it certainly does not help that various creationists use different rates and different units for those rates (eg, seconds per year, milliseconds per day, milliseconds per day per century) -- translating all the rates to the same units is one of the mathematical challenges. The creationist who complained about my misstatement did so based on the Walter Brown claim with which it did conflict, even though my misstatement was in line with the Hovind claim.

I hope to have the new page up within a month or two. I do still work for a living and I also have a life, so I am working on this in what little spare time I have.


Table of Contents


Abstract

This page discusses a popular young-earth creationist claim created in 1979, soundly refuted in 1982, and still being used by creationists, including professionals, even when they know full well that it is so false that it should be impossible to defend. I have yet to see any attempt to defend it, just a stubborn refusal to stop using it despite its sound refutation decades ago.

This is to my knowledge the oldest version of the claim and most likely the original:

Atomic clocks, which have for the last twenty-two years measured the earth's spin rate to the nearest billionth of a second, have consistently found that the earth is slowing down at a rate of almost one second a year. If the earth were billions of years old, its initial spin rate would have been fantastically rapid—so rapid that major distortions in the shape of the earth would have occurred.
(Evidence that Implies a Young Earth and Solar System by Walter Brown, Evidence for Creation Series, I.C.R. Midwest Center, 1979, as quoted by [1] Thwaites and Awbrey)

The claim and its fatal confusion centers around leap seconds, which actually work very much like leap years do. An official day in Coordinated Universal Time (UTC) is about two milliseconds shorter than a mean solar day. That means that every day that goes by UTC and mean solar time drift further apart by that daily difference, just as the calendar and the actual year drift apart by about a quarter of a day per year. For leap years, after four years the calendar and the actual year differ by about one day, so we add a day to the calendar to correct it. For leap seconds, after 12 to 18 months UTC and mean solar time differ by about a second, so we add a second to UTC to correct it, a leap second. Same idea, for the same reason and purpose, and with the same implications.

The creationist claim does not understand that that correction of UTC is the deal with the accumulation of error over time, so it confuses it with the rate at which the earth's rotation is slowing down. Every 12 or 18 months the discrepancy between UTC and mean solar time results in the accumulation of about one second of error, so the creationist claim mistakenly claims that the earth's rotation slows down by one second every 12 to 18 months (though different versions of the claim will vary).

Since the actual rate at which the earth slows down is 1.4 to 2.0 milliseconds per day per century (ie, after 100 years, the day will be 1.4 to 2.0 milliseconds longer than it had been -- USNO Earth Orientation (EO) Department and Time Service Department), that means that the creationist claim is using a false rate that is hundreds to tens of thousands of times too great, depending on which creationist claim you use. Those inflated rates cause their results to be inflated as well, resulting in their retrodiction that the earth would be spinning impossibly fast just millions of years ago. In contrast, retrodictions based on the actual rate have the earth spinning about twice as fast 4 billion years ago with a 12-hour day instead of the present 24 hours (eg, [1] Thwaites and Awbrey).

The claim first appeared in 1979 and was sound refuted in 1982 ([1] Thwaites and Awbrey), yet it continues to be used widely by creationists. In 2001, an organization ([2] Ontario Consultants on Religious Tolerance) tried to open a dialogue with 15 creationist websites using this claim by explaining what is wrong with the claim; all of the sites continued to use the claim despite knowing that it is completely false.

 


An Apology

After a while, you are going start to feel like I'm beating a dead horse. No, make that beating a bare patch of ground where there once was a dead horse. I apologize for that.

Basically, you already know what the claim is, that is it wrong, and why it is wrong. The rest is just explanation. Even though I do provide further information to help you understand the matter better, there is also the repeating of the claim and why it is false.

I will try to not bore you.

 


Sources

I am listing my sources here explicitly in response to a creationist's spurious complaint. However, that same creationist did also find an error in my wording which led to this rewriting, so constructive comments from creationists do help.


Official Sources

The information about leap seconds and the actual rate at which the earth's rotation is slowing down (ie, about 2 milliseconds per day per century) come from two pages, both from departments within the United States Naval Observatory (USNO) -- the links are to their respective pages on leap seconds:

You should note that the USNO is one of the agencies closely involved in international time-keeping, the other two being the National Institute of Standards and Technology (NIST) and the International Bureau of Weights and Measurements (BIPM, le Bureau international des poids et mesures). Since these are the people who manage and maintain official timekeeping, that means that these are the people who really know what they are talking about when it comes to time, leap seconds, and the rate at which the earth's rotation is slowing down (which is constantly monitored and measured empirically by the International Earth Rotation and Reference Systems Service (IERS)).

You should also note that those pages also directly address the creationist mistakes and dispell the confusion about leap seconds which led to the creationist claim in the first place.


Personal and Professional Experience

For the past two decades I have been working as a software engineer on a product line which incorporates GPS receivers for precise timing. As such, I am very familiar with what leap seconds are and how they are used. I am also familiar with aspects of official timekeeping.

In addition, my interest in astronomy and other aspects of science spans more than half a century. I had even studied orbital mechanics on my own in college. While I am far from being an expert, I can use my knowledge to explain the astronomical basis for timekeeping and various aspects that affect timekeeping. In the course of those explanations, I will refer you to the appropriate Wikipedia pages for further explanation as well as far more meaningful graphics than I could supply.


"Creation/Evolution" Sources

Even though I refer you to those sources as I use them, consider this to be a centralized bibliography:
  1. As the World Turns: Can Creationists Keep Time? by William M. Thwaites and Frank T. Awbrey, Creation/Evolution, Issue IX, Summer 1982, pp.18-22.

  2. An unsuccessful attempt to correct an error on young-earth creationist websites., Ontario Consultants on Religious Tolerance, 2001.

  3. Evidence that Implies a Young Earth and Solar System by Walter Brown, Evidence for Creation Series, I.C.R. Midwest Center, 1979. Cited and quoted by Thwaites and Awbrey [1].

  4. EVIDENCE THAT IMPLIES A YOUNG EARTH AND SOLAR SYSTEM by Walter Brown, 1981. Included in a PDF, “YOUTH CREATION CONFERENCE” Notes, compiled by Creation Evidence Museum Staffwriter David V. Bassett, MS (Graduate, Institute for Creation Research), date unknown (downloaded 2003 Sep 03). Its leap second claim is virtually identical to [3] except for a typographical error noted in the discussion below.

  5. "The Riddle of the Leap Second" by Arthur Fisher, Popular Science, Vol. 202, March, 1973, pp. 110- 113, 164-166. Cited by Brown, [3] and [4]. Also "cited" by other creationists employing the standard dishonest creationist practice of falsely claiming another creationist's source as their own while not mentioning their own creationist source (in this case, Walter Brown [3]).

  6. The Creation-Evolution Controversy by R. L. Wysong, 1981, page 164. Falsely cites Fisher [5] when his real source was Brown [3].

  7. The Collapse of Evolution by Scott Huse, 1983, page 25. Cites Wysong [6], albeit erroneously: Huse cites page 455 whereas the claim is on page 164.

  8. "Earth's rotational speed is slowing down", "Seminar 1: The Age of the Earth, part b", Kent Hovind Seminar Lectures, 2007. Transcribed by "The Wise Old Goat" Michel Snoeck, 2013.

  9. Universe Is Not "Billions of Years" Old by Kent Hovind, date unknown. Currently renamed to Evidence from Earth of a Young Earth by Hovind's son, Eric Hovind, who also now claims authorship -- so much for any notion of honor among creationists. Kent Hovind cites himself [8] as well as Huse [7].

  10. A STUDY OF A LOCAL CREATIONIST INSTITUTION, Paul J. Wendel, Kent State University College and Graduate School of Education, Health, and Human Services, May 2008. This is a student dissertation which also examines Hovind's claim [8]. In that claim, Hovind used an article from the local newspaper, Pensacola News Journal. Wendel verified that Hovind quoted that article correctly, which means that it was the reporter or his source who got the facts wrong.

  11. How Creationism Taught Me Real Science #19, Earth's Rotation, Tony Reed, YouTube video.

 


Summary

This is a short explanation of leap seconds and a history and refutation of the claim.


At the beginning of the 20th century, astronomers discovered that the earth's rotation is slowing down. Through constant observation, monitoring, and measurements, the rate of deceleration has been determined empirically to be 1.4 to 2 milliseconds per day per century, which is often rounded up to 2 ms / day / century. What that rate means is that after 100 years the day will be 1.4 to 2.0 milliseconds longer than it had been.

From their calculations based on astronomical observations made between 1750 and 1892, astronomers determined the length of a second in 1900. That second eventually became the international standard second (SI Second) that is used by Coordinated Universal Time (UTC). As the Time Service Department of the US Naval Observatory describes the history on their leap seconds page:

Historically, the second was defined in terms of the rotation of the Earth as 1/86,400 of a mean solar day.  In 1956, the International Committee for Weights and Measures, under the authority given it by the Tenth General Conference on Weights and Measures in 1954, defined the second in terms of the period of revolution of the Earth around the Sun for a particular epoch, because by then it had become recognized that the Earth's rotation was not sufficiently uniform as a standard of time.  The Earth's motion was described in Newcomb's Tables of the Sun, which provides a formula for the motion of the Sun at the epoch 1900 based on astronomical observations made during the eighteenth and nineteenth centuries.  The ephemeris second thus defined is

        the fraction 1/31,556,925.9747 of the tropical year for 1900 January 0 at12 hours ephemeris time.

This definition was ratified by the Eleventh General Conference on Weights and Measures in 1960.    Reference to the year 1900  does not mean that this is the epoch of a mean solar day of 86,400 seconds.  Rather, it is the epoch of the tropical year of 31,556,925.9747 seconds of ephemeris time.  Ephemeris Time (ET) was defined as the measure of time that brings the observed positions of the celestial bodies into accord with the Newtonian dynamical theory of motion.

The ephemeris second was used in the 1950's and 60's to calibrate atomic clocks, such that the resultant atomic second was of the same length as the ephemeris second. When the atomic second formed the basis of the international standard second (SI second) in 1967, that made the SI second the same length as the ephmeris second, effectively the same length as a second in 1900.

And since a century has transpired since 1900, that means that a mean solar day is now about two milliseconds longer than a UTC day. Thus mean solar time and UTC drift apart by 2 milliseconds every day, accumulating into a one second discrepancy after about 18 months. Therefore in order to eliminate that discrepancy and resynchronize the two clocks (ie, adjust UTC to match mean solar time), we need to correct UTC by periodically adding an extra second to UTC, a "leap second", in a manner analogous to and for exactly the same reasons that we add an extra day to the calendar every leap year to correct for the quarter-day of error the calendar accrues every year.

Towards the end of the 1970's a flood of articles was published in a wide variety of magazines, mostly technical and science-oriented, discussing and describing the upcoming NAVSTAR Global Positioning System (GPS). That system maintains its time as GPS time, the total number of SI seconds since the start of GPS time (Sunday, 1980 Jan 06 0000h). GPS satellites also broadcast the current UTC offset to add to GPS time to obtain UTC time. That UTC offset is the number of leap seconds that have been added since the start of GPS time, at which time nine (9) leap seconds had already been added to UTC -- eighteen (18) more leap seconds have been added since then (ie, as of 2017 September), giving us a UTC offset of 18. GPS satellites also broadcast information about the next leap second event. Therefore, leap seconds are very much a part of GPS, so they were mentioned in those articles.

A creationist reading those articles (most likely Walter Brown, who published the earliest occurances of this claim in 1979) misunderstood what leap seconds were and wrongly assumed that they represented the rate at which the earth's rotation was slowing down. Thus he stated that the earth's rotatation was slowing down at "a rate of almost one second a year". From that, he and every creationist who repeated and added to this claim arrived at the conclusion that the earth could not possibly be ancient since an ancient earth billions of years ago had to have had an impossibly rapid spin -- some even describe the spin a few millions of years ago as being impossibly rapid. A favorite feature of this claim is to describe how that impossibly rapid spin would have grossly distorted the shape of the earth, flattening it out like a pancake or a pizza.

The claim is false because it is based on not understanding what leap seconds actually are and what they actually do and mean. That misunderstanding leads to creationist rates of deceleration which range from hundreds to several thousands of times too great, depending on which creationist you're listening to. Those grossly exaggerated rates lead to absolutely ludicrous and utterly false conclusions. In contrast, the classic 1982 refutation of this claim ([1] As the World Turns: Can Creationists Keep Time? by William M. Thwaites and Frank T. Awbrey, Creation/Evolution, Issue IX, Summer 1982, pp.18-22) uses the actual rate to calculate the length of a day 4 billion years ago as having been 12 hours, then points out the non-flattened shape of Jupiter with a 10-hour day.

Despite the claim having been soundly refuted, the creationist community continues to use it, now nearly four decades later, even when they know that it is false. In 2001 (nearly two decades after the claim was refuted), a Canadian organization, Ontario Consultants on Religious Tolerance, attempted to discuss the claim with creationists ([2] An unsuccessful attempt to correct an error on young-earth creationist websites.). They found fifteen sites that used the claim and explained the situation to them. Most of the webmasters simply ignored them while others either refused to discuss it, insisted that the claim was correct, or else pretended to be reasonable in order to "smile you out the door." The end-result was that all of the websites continued to post the claim unchanged. Those creationists' actions amount to deliberate lying.

 


Time-Keeping and Leap Seconds

NOTE:
Normally when refuting a creationist claim you first present the claim and then explain what's wrong with it. This time, I'm going to present the facts first and then present the claim. My reasoning is that by doing it that way, while I'm presenting the creationist claim you will be able to see immediately what's wrong with it every step of the way.

Besides, by having read the abstract you already know basically what the claim is and why it is wrong. So now all this is explanation.

 


"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly-wobbly ... timey-wimey ... stuff."
      -- The 10th Doctor in Blink


Besides being a neat line that really caught on, that quote also alludes to the Time Lords, a nickname that some nerdy types have given to the scientists and technicians at USNO, NIST, and BIPM who maintain official time, Coordinated Universal Time (UTC). Very little about timekeeping is simple and straight-forward, but rather every attempt at a definite and accurate definition of units of time comes with its own complications and problems that need to be solved.

Start with the day. One earth rotation resulting in one solar cycle, noon to noon. Once we have that, we can divide it down to hours, minutes, and seconds as well as to scale it up to weeks, months, and years. Simple enough, or so it seems.

The Year

The year is the first complication, one which actually leads more or less directly to the idea behind leap seconds. A year is one revolution about the sun (or at least we realize that now), Vernal Equinox to Vernal Equinox. 365 days.

Well, not exactly, actually about 365.25 days. Calendars are restricted to counting whole days, but if you mark off a year as 365 days then after a year you're off by a quarter of a day; ie, the calendar is in error by a quarter of a day. Then another year goes by and you accrue another quarter day of error so that now the calendar is off by half a day. And that error will continue to grow by another quarter of a day every year after that. You cannot let that happen, because it is very important for agriculture that you know when the Vernal Equinox, the First Day of Spring, and the other cardinal points (ie, Autumnal Equinox, Summer Solstice, Winter Solstice), the starting dates of the seasons, are every year. So the solution was the Julian Calendar introduced by Julius Caesar in 46 BCE, in which a year was 365 days except for every fourth year which had an extra day added to it.

That's the leap year idea which you should already be familiar with. It introduced a new problem: It over-corrected the calendar. Instead of being 365.25 days long, a year is actually a little shorter, about 365.24217 days long. That resulted in the Julian Calendar adding three days too many every 400 years, which caused the seasons to drift away from their starting dates. That led to the Gregorian Calendar in 1582 which removed those extra days and modified the leap-year rules to prevent them from happening again. But since it was a Catholic idea, the Protestants (eg, the British and their colonies such as in America) didn't accept it until a couple centuries later and the Orthodox churches not until the early 20th Century (eg, in 1924 by Greece, the last hold-out).

The Day

As complicated as the year turned out to be, the day is worse. We defined the day as one rotation of the earth being one solar cycle, noon to noon. Right? Wrong!

As the earth rotates, it's also revolving about the sun. In the time of one rotation, the earth moves about one degree in its orbit (more or less, depending on where it is in its orbit). So, start measuring the day when the sun is at noon. Exactly one rotation later, the sun isn't back at noon yet. Instead, it appears to be lagging about one degree to the east, such that the earth needs to continue to rotate one more degree before the sun is at noon again. Noon to noon is called a "solar day" which is about 24 hours, whereas one full rotation of 360° is called a sidereal day (ie, "star day", since you end up pointing to the same place in the star field), which is about 23 hours, 56 minutes, 4.0916 seconds long.


MATH NOTE:
For time calculations involving degrees of longitude, divide 360° by 24 hours. You get that one degree of longitude equals four minutes of time. Thus the difference between a mean solar day and a sidereal day is about four minutes because it takes about four minutes for the earth to rotate about one degree.

Another application of this is converting from standard time to local time. You live within a standard time zone that is about 15 degrees wide (if one degree is four minutes of time, then 15 degrees are one hour). The time within that time zone is the local time on the standard time meridian, which is a multiple of 15° (eg, 120° for Pacific Standard Time). So to calculate local time, find the difference between your local longitude and your standard time meridian in degrees, multiply that by 4, and add or subtract that many minutes and seconds to/from the standard time. And if you're reading time off a sun dial, then do the reverse to convert local time to standard time. Though if you're using a sun dial, then you'll also need to apply the Equation of Time described below.


It turns out that there are other problems with the solar day: each solar day is a different length than the next. You see, the extra time it takes to line the sun back up again depends on how far along its orbit the earth has moved. That varies day by day because earth's orbit is elliptical which causes the earth's orbital velocity to vary. According to simple orbital mechanics, the earth is moving faster when it's closer to the sun and more slowly when it's farther away from the sun. As a result, the solar day is longer when the earth is closer to the sun because the earth had moved farther along its orbit and so has to rotate even farther to line up with the noon-day sun. Similarly, the solar day is shorter when the earth is farther away because the earth hadn't moved as far and so doesn't have to rotate as far to hit noon.

To solve that problem, astronomers and timekeepers determined the average length of the solar days and came up with mean solar time -- "mean" is a kind of an average, the midpoint between two extremes. That is why we used to use Greenwich Mean Time (GMT, since superceded by UTC) and I keep referring to a "mean solar day". An actually occurring solar day is called an "apparent solar day" and the difference between an apparent solar day and a mean solar day for a given time of the year is shown by a graph, the equation of time, which is mounted on more precise sundials to allow you to convert the apparent solar time you read off the dial to the mean solar time to set your pocket watch to. That is related to the analemma, that lop-sided figure-8 you saw in the Pacific Ocean on globes all those years you were growing up.

The Second

I heard a story from the late 1800's about an editorial in a magazine -- Scientific American, as I seem to recall -- which stated that we have discovered everything there is to discover and invented everything there is to invent. If that story is true, then that author was incredibly wrong.

It was around that time that astronomers were beginning to suspect that the rate at which the earth rotates is not constant, but rather is slowing down. By 1920, they had confirmed that suspicion. This presented astronomers and physicists with an enormous problem. Time is a factor in most of the equations they work with, so they could not afford to use a unit of time that is based on a time source that is changing; the second must remain constant. Astronomers needed to find some other time base, one that doesn't change.

Astronomers' solution to that problem was ephemeris time, which was arrived at basically by using precise observations to solve for time. In reality, it was more complicated than that as you can read in the Wikipedia article, ΔT ("delta time"). The calculations are based on astronomical observations made between 1750 and 1892, centered around the year 1820. The resultant ephemeris time, accepted as a standard in 1952, was based on an epoch date of 1900 January 0. Therefore, the ephemeris second is the length of a second in 1900, though some sources give 1820 as the base date.

As physicists developed atomic clocks, they used ephemeris time to calibrate them. Thus when the atomic second was defined in 1967 as 9,192,631,770 cycles of the Cesium-133 atom at zero magnetic field, it was the same length as an ephemeris second, which in turn was the same length as a mean solar second in 1900. I think you can see where this is leading us.

When Coordinated Universal Time (UTC) was adopted in 1970, it used atomic time. Hence, one second in UTC is the length of one mean solar second back in 1900 and one day in UTC is equal to 86,400 of those seconds. Since the rate of the slowing of the earth's rotation is about 2 milliseconds per day per century and it has been a little more than a century since 1900, that means that a mean solar day now is about 2 milliseconds longer than a day according to UTC.

Leap Seconds

Most people wouldn't notice that small difference, except for the requirement that UTC be synchronized with mean solar time. IOW, when UTC says it's noon, then the sun must also say it's noon (disregarding other offsets, such as daylight savings and distance from the time zone's standard time meridian and the equation of time). It is because of that requirement that we must correct UTC periodically with leap seconds.

Think it through. We have two clocks: UTC and the sun (ie, mean solar time). Start them both in sync with each other -- actually, you can only set or change the UTC clock. Zero error, initially. At the end of one day, the UTC clock is behind mean solar time by two milliseconds; UTC has an error of 2 ms. At the end of the second day, UTC is behind by an additional 2 ms; UTC now has an error of 4 ms. And so on, day after day, with UTC falling further behind as its error grows by 2 ms every day. At the end of a year (365 days), UTC's error has grown to about 0.73 seconds. At the end of 500 days (just under 18 months), UTC's error has grown to about a full second. So at that point we add a second, a "leap second", to UTC to sync it back up with mean solar time.

That's the idea behind leap seconds and the reason for them, essentially the same idea and reason as for leap years. However, as simple and straight-forward the idea of and reason for leap seconds are, it gets complicated in practice (so what else is new?):

  1. Instead of waiting for UTC to be off by a full second, in practice they try to keep the difference down to less than ± 0.7 seconds. So a leap second correction would actually set UTC a little ahead of mean solar time, but don't worry because it will fall behind again soon enough.

  2. While the earth's rotation is slowing down over long periods of time, it can also vary considerably over short periods of time, even daily, sometimes speeding up and sometimes slowing down, in response to a large number of different forces. These effects can be seen graphically on the leap second page of the Time Service Department at the USNO, as well as in the Wikipedia article on leap seconds. As a result, leap seconds can often occur within a year of each other instead of 18 months apart, or else not be needed for years at a time (eg, the seven-year gap between Dec 1998 and Dec 2005).
Therefore, the earth's actual rotation has to be monitored constantly. That service is provided by the International Earth Rotation and Reference Systems Service (IERS, from its former name, International Earth Rotation Service). It is the IERS that monitors and measures the earth's rotation, tracks the difference between UTC and mean solar time, determines when a leap second is needed, and announces an upcoming leap second event. They also give us the actual length of the mean solar day and hence how much the earth's rotation has slowed down since 1900.

 

An additional wrinkle in the question of the long-term rate at which the earth's rotation is changing is that that rate is known to not be constant. Obviously, we have the short-term effects which are constantly causing the earth's rotation to speed up or slow down. But there are also factors which cause the long-term rate to change, such as the effects of the positioning and distribution of land masses on tidal friction or the post-ice-age rebounding of the crust in the northern latitudes.

The lengths of the day on the ancient earth, as well as ancient climate conditions can be determined through geological evidence such as varves and tidal rhythmites. For example, coral growth forms varves, visible layers in which you can see daily, seasonal, and annual growth patterns. One such example is fossil coral from the Devonian (circa 400 million years ago) showing there to have been about 400 days in the year, hence each day would have been about 22 hours long.

Deposits left by the tides form layers called tidal rhythmites. In his video, How Creationism Taught Me Real Science #19, Earth's Rotation, Tony Reed cites a geology paper: Precambrian length of day and the validity of tidal rhythmite paleotidal values, George E. Williams, Geophysical Research Letters, Vol.24, No.4, 15 Feb 1997, pages 421-424. Reed also displays a table from that paper showing the length of the day at various points in the earth's past; eg, 17 to 19 hour-long days about 2.5 billion years ago (2.5×109).

However, since the creationist claim extrapolates back using what it believes to be the current rate, we will do the same in order to compare the effects of the actual current rate with theirs. In Doing the Math we will also compare our results with those from Dr. Williams' paper.

 

Summary

These are the points I want you to get from this section:
  1. The standard time units of UTC last matched those of mean solar time in 1900. In the century since then, the mean solar day has become about two milliseconds longer than the UTC day.

  2. Every day that passes, UTC falls behind mean solar time by about two milliseconds. This means that the discrepancy between UTC and mean solar time increases by an additional 2 ms every day. After 500 days of that, the discrepancy would be about one second.

  3. The only reason for leap seconds is to correct that discrepancy between the two clocks, UTC and mean solar time.

  4. There is no direct connection between leap seconds and the slowing of the earth's rotation. At most, there is a very indirect connection in that the discrepancy between the time units of UTC and mean solar time was created by the slowing of the earth's rotation.

  5. Even if the earth's rotational rate were to stop slowing down and remain constant from now ever after, we would still need leap seconds because the mean solar day would still be two milliseconds longer than the UTC day. By analogy, consider that we need leap years because a complete orbit is a quarter day longer than a calendar year and also consider that the length of the year (ie, one complete orbit) is not changing.

  6. There is absolutely no connection whatsoever between how often we add leap seconds and the long-term rate at which the earth's rotation is slowing down. A leap second does not, in itself, signal the slowing of the earth’s rotation, but rather the increased or decreased frequency of leap seconds over time signals the slowing down or speeding up of the earth’s rotation. You cannot possibly use leap seconds to determine the long-term rate of rotational deceleration!

  7. The long-term rate at which the earth's rotation is slowing has been determined empirically through direct observation and measurement. That rate is about two milliseconds per day per century, according to two departments within the United States Naval Observatory (USNO): The Earth Orientation (EO) Department and the Time Service Department. And that rate has nothing to do with how often we add leap seconds.

 


The Claim

This is a rather popular and enduring creationist claim, even though it is one of the more blatantly false of their claims and it was completely refuted in 1982, a few years after it was created. It also reveals creationists' strong hatred for truthfulness and honesty, since creationists persist in using it even after they learn how undeniably false it is.

Here is the oldest form of the claim by Walter Brown, its apparent creator, as quoted in the claim's classic 1982 refutation (As the World Turns: Can Creationists Keep Time? by William M. Thwaites and Frank T. Awbrey, Creation/Evolution, Issue IX, Summer 1982, pp.18-22):

Atomic clocks, which have for the last twenty-two years measured the earth's spin rate to the nearest billionth of a second, have consistently found that the earth is slowing down at a rate of almost one second a year. If the earth were billions of years old, its initial spin rate would have been fantastically rapid—so rapid that major distortions in the shape of the earth would have occurred.
(Evidence that Implies a Young Earth and Solar System by Walter Brown, Evidence for Creation Series, I.C.R. Midwest Center, 1979)

I do not have a copy of their original source, but I can verify that quote since it also appears in a PDF file, “YOUTH CREATION CONFERENCE” Notes (cited above in my Sources section), which I downloaded in 2003. The claim included in that PDF is dated March 1981 and is identical except that it contains a typographical error that replaces "the last twenty-two years" with "the last 2 years" -- 22 years would be much more in keeping with the actual history of the development of atomic clocks. It also includes Brown's bibliography, which Thwaites and Awbrey had moved down into their own bibliography. Since the claim referenced a November 1977 article (Jack Fincher, “And Now, Atomic Clocks,” Readers’ Digest, Vol. III, November 1977, p. 34), that would support the assumption that this is the original claim and that Walter Brown is "Creationist Zero" for its spread; i.e., that he's the claim's creator.

Since you have read the previous section (Time-Keeping and Leap Seconds -- at least the summary if nothing else) as well as this page's Abstract and Summary sections, you already know what Brown's mistake is and why this claim is wrong. He mistook the adding of a leap second at the end of a year to be mean that the earth's rotation had slowed so much in that one year that that year ended up being one second longer. That would translate to each day having been about 2.74 milliseconds longer, giving us a rate of 2.74 milliseconds / day / year. However, the actual rate is about 2 milliseconds / day / century, so Walter Brown's rate is about 137 times too great. Since his conclusion of a "fantastically rapid" initial spin rate is based on that over-estimated deceleration rate, it too is inflated out of proportion.

Unfortunately, he does not tell us just exactly what his "fantastically rapid" initial spin rate is supposed to have been, but rather he just waves his hands and makes assertions. However, we shall see below how Kent Hovind uses a different rate which he does use to predict the earth's spin in the past. In that case, we shall see that Hovind's claimed rate turns out to be over 18,000 times too great.

Getting back to Walter Brown's claim, of course you can readily see that his rate of 2.74 ms /day / year does not reflect the rate at which the earth's rotation was slowing down, but rather the rate at which the UTC clock was accumulating error, such that after a year you would need to add a leap second to sync it back up with mean solar time.

Brown made a mistake because he didn't understand what leap seconds are nor what purpose they serve. He relied on other sources, which apparently didn't do a good job of educating him. I found one of those sources, which I cited above, "The Riddle of the Leap Second" by Arthur Fisher, Popular Science, Vol. 202, March, 1973, pp. 110- 113, 164-166. From page 164 of that article:

But, to use atomic clocks to keep the time of day, time experts had to lengthen or "offset" each second slightly to make it correspond to Earth's lagging rate. This offset atomic time was called Universal Coordinated Time (UTC).

On Jan. 1, 1972, a new time scale, agreed on by the International Radio Consultative Committee, went into effect. There will be no more offsetting of clock rates; UTC will be a pure atomic scale. But the rule is that it must not be allowed to get more than 0.7 seconds out of kilter with Earth time -- actually the navigator's time UT1. Whenever the gap threatens to exceed that margin, in the judgment of Bernard Guinot, head of the International Bureau of Time (BIH, its acronym in France), a leap second will be added (or subtracted, should the Earth decide to speed up). The process is analogous to adding leap years, only not so predictable.

Monsieur Guinot, whom I met in Boulder, told me that he expected that about one leap second per year would be needed, on average, and that the one added on June 30, 1972, would probably suffice until the following June (the BIH prefers to add the leap second either at the end of June or the end of December, to avoid confusion).

But he also said it would be hard to know in advance. In that he was certainly correct, for since that time the Earth slowed down just enough more to require another leap second in 1972 -- a step that made celebrating New Year's Eve even more confused than it usually is. And since 1972 was a leap year to begin with, that made it the longest calendar year ever -- in spades.

Now, I understood what the author was trying to say there, but then I have been working with leap seconds for about twenty years now since our products employ embedded GPS receivers. But I can see how that could have been confusing for someone who didn't already understand anything about leap seconds, someone like Walter Brown.

Brown's claim was based entirely on a mistake. While Walter Brown appears to no longer use that claim, the rest of the creationist community still continues to use it. Other creationists immediately adopted the claim and expanded upon it, mostly to describe those "major distortions in the shape of the earth" more graphically by describing that "ancient earth" as being flattened "to a flat pancake", or a pizza depending on your taste in flat food.

As is so sadly typical of the genre, most creationists' versions of the claim look like they are just repeating what other creationists have said without having done any actual research themselves nor any of the math that their claim depends on. We see this in how they mostly repeat and reword other versions of the claim as well as employ a lot of hand-waving -- my Lindy teacher's advice about dancers who use jazz hands, another form of hand-waving, is that they're trying to direct your attention away from how they're messing up their footwork. We will see examples of that in A History of the Claim where we trace one line of transmission of the claim from Walter Brown to Kent Hovind, as well as when we evaluate which claims to examine more closely when we do the math.


Most versions of the claim are fairly stale and vague rehashes (ie, a lot of hand-waving instead of specific numbers), whereas Kent Hovind's expanded version is very colorful and contains specific numbers that we can work with. It is also rather popular and gets repeated a lot, so we should examine it here even though it's not in the direct line of descent of the claims we examine in A History of the Claim, but rather it is the source that Hovind had cited in his claim (ie, in his one-line claim, Hovind cited his own seminar video as a source).

BTW, Hovind actually has multiple versions of the claim, two of which I am familiar with and which I include on this page. The other version is much shorter, just one sentence in a list of standard "young earth evidences": "The slowing spin of the earth limits its age to less than the 'billions of years' called for by the theory of evolution." What is important about that version is that Hovind broke from creationist tradition by citing his actual creationist source, Scott Huse, which led me on my research into this claim tracing it back to Walter Brown, "Creationist Zero", but more about that later in A History of the Claim.

In that shorter claim, Hovind also references himself from one of his seminar videos. This is normally a problem for researchers, because Hovind is notorious for committing as few of his claims to print as possible, making it that much more difficult to research his claims. Fortunately Michel Snoeck, "The Wise Old Goat" (whom I cite above as a source), transcribed Hovind's 2007 videos, from which I copy-and-pasted the following (from http://www.wiseoldgoat.com/papers-creation/hovind-seminar_part1b_2007.html#rotationalspeed):

Slowing Earth

Another factor. The earth is spinning—we are turning around. How many knew that already? We are turning around. You know the earth is going a little over 1,000 miles an hour at the equator, but the earth is slowing down. It is actually slowing down 1000th of a second everyday. Pensacola News Journal, 1990, said on December 6, "Earth’s rotation is slowing down, June will be one second longer than normal. The earth is slowing down 1000th of a second every day." Astronomy magazine announced, 1992 in the June edition, "Earth’s rotation is slowing down, June is going to be one second longer than normal." We will have to have a "leap second." A leap second? Most people have heard of leap year, but lots of folks have never heard of leap second. Did you know we have a leap second about every year and a half now because the earth is slowing down? Now kids this is going to be kind of complicated so listen carefully. The earth is spinning but it is slowing down. So that means that it used to be going faster. How many can figure that out with no help? Okay several. Well, now if the earth is only 6,000 years old that is not a problem. It was probably spinning a little faster when Adam was here. Maybe they had 23 and 1/2 hours in a day. They would not notice, they did not have a watch anyway. Some of these folks want you to believe that the earth is billions of years old. Now that would make a problem. If you go back a few billion years, the earth was spinning real fast. Your days and nights would be pretty quick! Get up, go to bed! Get up, go to bed! Get up, go to bed! You would never get anything done. And a centrifugal force would have been enormous, would have flattened the earth like a pancake. The winds would have been 5,000 miles an hour from the Coriolis effect. You think the dinosaurs lived 70 million years ago? I know what happened to them? I know what happened to them... they got blown off! No they did not live 70 million years ago, folks; it simply cannot possibly be true.

Very colorful and very humorous. And completely wrong, as you already know.

But this claim of Hovind's does something that the other versions don't: it presents the results of an actual calculation based on the claimed rate. While the other claims offer little more than the usual creationist hand-waving, here we see Hovind presenting an actual rate (even though it is wrong) and calculating the length of a day in the past based on that rate. Specifically, he applied the rate of 1 ms per day per day to determine that the length of a day 6,000 years ago would have been about 23 hours 30 minutes. Since my own calculations based on that rate came out to 23 hours 23.5 minutes, I basically reproduced his results and verified that that is how he had interpreted and applied that rate. Then I extended his rate in that same manner further back in time and ended up with a day about zero length a quarter of a million years ago. Obviously quite ridiculous.

That verification I performed also served a second purpose, since in this claim Hovind presents two different rates, the other being about the same as Walter Brown's (ie, 18 months instead of 12). Thanks to Hovind's calculation and my verification of it, we know which of the two rates he actually used.

 

So how much greater than the actual rate are the creationist rates? I still need to work that out rigorously, but in the meantime here are some back-of-the-envelope calculations.

To start with, in order to compare rates we need to get them into the same units. Hovind's rate is in milliseconds per day per day, so let's shoot for making that the working standard.

The actual rate is about 2 milliseconds per day per century. That would work out to be about 54.758 nanoseconds per day per day. One nanosecond is one one-billionth (10-9) of a second, so one nanosecond is one one-millionth of a millisecond. Thus 54.758 nanoseconds / day / day would be 0.000054758 milliseconds / day / day.

Walter Brown's rate, which could be considered the standard creationist rate, is given as "almost one second a year." That has been presented by various creationists as either either one second every 12 months or one second every 18 months -- the general rule of thumb for the frequency of the addition of a leap second is once every 18 months, though that's complicated by several factors affecting the earth's rotation (see Leap Seconds above). Let's consider those separately:

First let's see how Hovind's rate compares to the actual rate. Dividing 1 milliseconds / day / day by 0.000054758 milliseconds / day / day, we get 18262.17. Therefore, Hovind's rate is about 18262 times too great. Ridiculously too great and hence his ridiculous results.

How does the rate of one second in 12 months compare? Dividing 0.0075 milliseconds / day / day by 0.000054758 milliseconds / day / day, we get 137. Therefore, that rate is 137 times too great.

Now how does the rate of one second in 18 months compare? Dividing 0.005 milliseconds / day / day by 0.000054758 milliseconds / day / day, we get 91.3. Therefore, that rate is 91 times too great.

Well of course, Hovind's rate being 18262 times too great will produce ridiculously false results. This is significant, since it's only Hovind's claim that makes any kind of calculated retrodiction.

Since Brown's rates are much lower, to the order of 100 times too great, you might think that they are more reasonable. Well, they're still too large, but there's another problem with them. We have no calculations of what their effects are supposed to be. All we have for those rates is a lot of hand-waving. And we know that too much hand-waving often means that something is being covered up, something that they don't want us to see.

We can see an example of creationist hand-waving being used to hide the truth. In another creationist claim (Kent Hovind's solar-mass-loss claim), Hovind presented the rate at which the sun is losing mass, about 5 million tons per second, and then started waving his hands to assert that billions of years ago the sun would be so incredibly more massive and larger and its gravity would have been so incredibly great that it would have sucked the earth in. However, when we use that rate of mass loss to actually calculate the sun's mass 5 billion years ago, it would have been only a few hundredths of one percent more and hence its mass and gravity would have been minimally greater, "sucking the earth in" by only about 60,000 miles.

The point is that until we actually calculate the effects of the creationists' far greater rates of rotational deceleration, we don't have anything to go on except for their frantic hand-waving. They certainly did not do the math (except for Hovind in this one case), so we will need to do the math.

 

At this point those are little more than rough figure of merit comparisons to give you a basic idea of how far off the creationist claims are. I will recalculate all that more rigorously when we buckle down to do the math. At that same time, I will examine the calculation methods that have been used for validity and to attempt to derive a valid method for calculating the length of the day given a particular rate of deceleration.

 

Paul J. Wendel also examines Hovind's claim in his dissertation, A STUDY OF A LOCAL CREATIONIST INSTITUTION (Paul J. Wendel, Kent State University College and Graduate School of Education, Health, and Human Services, May 2008, pp 277-290). Wendel writes:

The Leap Second
. . .

Hovind, Baugh, the Pensacola News Journal, and the Fossil Museum all seem to misapprehend the fact that if the earth were to stop decelerating today, i. e. if the earth were to maintain its present rate of spin in the future and no change were made to the atomic-clock-based definition of the second, leap seconds would continue to be needed. This is because atomic clocks run 0.0025 seconds faster per day than the earth’s spin rate would indicate. Therefore every 400 days or so a leap second is necessary,61 even if the earth continues at its present rate of spin. The fact that the earth is slowing means that over time, leap seconds will become more frequent. One hundred years from now, about two leap seconds will be needed per year (Nelson et al., 2001, p. 524). On the other hand, 22 leap seconds were added from June 1, 1972 to December 31, 1998 (nearly one per year), but the next leap second was not added until December 31, 2005 (Steyaert, 2005). This seven-year hiatus indicates that the earth actually sped up slightly during this time. Thus a leap second does not, in itself, signal the slowing of the earth’s rotation, but rather the increased or decreased frequency of leap seconds over time signals the slowing down or speeding up of the earth’s rotation.62

As noted above, the earth-rotation-based day presently lengthens by 1.4 ms every century, but Hovind, Baugh, the Pensacola News Journal, and the Fossil Museum assume that the day lengthens by 1 second every year. At the latter rate of deceleration, the earth would have spun twice as fast only 43,000 years ago.63 But at the former and accurate rate of deceleration, the earth would have spun twice as fast about 3 billion years ago.64 This estimate is substantiated by fossil corals which exhibit daily growth rings as well as annual growth rings. Study of these corals reveals that about 370 million years ago, a year included between 385 and 410 days (Nelson et al., 2001, p. 512).


61 (0.0025 seconds / day) (400 days) = 1.000 second

62 In technical terms, Hovind, Baugh, The Pensacola News Journal, and the Fossil Museum have conflated angular speed with angular acceleration.

63 At twice the spin rate, the day would have been 12 hours = 43,200 seconds shorter. (43,200 seconds) ÷ (1.000 second / year) = 43,000 years.

64 At twice the spin rate, the day would have been 12 hours = 43,200 seconds shorter. (43,200 seconds) ÷ (0.0014 seconds / hundred years) = 3.1 billion years


Nelson, R. A., McCarthy, D. D., Malys, S., Levine, J., Guinot, B., Fliegel, H. F., et al. (2001). The leap second: Its history and possible future. Metrologia, 38(6), 509- 529.

Steyaert, C. (2005, December). Save the leap second. Sky & Telescope, 134.

Not only does Wendel say the same thing that I've been telling you (in case you needed a second opinion), but he also was able to find and read that Pensacola News Journal article and verified that it is indeed the source of that one-millisecond-per-day rate that Hovind cites. In addition, he provides us with two calculations that we can verify and discuss below when we do the math.

 

At this point I should mention that in an earlier version of this page I had made a slight misstatement. After presenting Walter Brown's original claim and discussing it, I wrote:

Creationists claim that it's slowing down by one second per day every 12 to 18 months; ie, that after 12 or 18 months, the day will be one second longer.
That last part is not what's predicted by Walter Brown's original claim as a creationist pointed out to me. I had since rewritten that as follows, though that has also since been rewritten:
Creationists claim that it's slowing down by one second every 12 to 18 months, thus requiring the addition of a leap second to compensate for that "lost second." That would translate to each day becoming longer by 1.8 to 2.7 milliseconds, which would amount to a full second in 12 to 18 months.

However, my original statement is almost exactly what Kent Hovind is claiming when he says that the earth "is actually slowing down 1000th of a second everyday." At that rate, at the end of 1,000 days then each day would be one second longer. 1,000 days is about 2-3/4 years which is about 33 months, about twice his other rate of one second every 18 months and twice my mistaken statement.

Therefore, I wasn't really wrong in my original statement of what creationists are claiming, it was just that I was thinking specifically of Kent Hovind's claim.

 

But still, all these claims and their refutations leave us with a confusion of rates using different units and how they are to be applied and what they are to mean. That is why we will eventually need to actually do the math, so that we can analyze and compare them all with each other.

 


A Proposed Dialogue

You now know why the claim is wrong, but you had to learn a number of facts along the way. How then to present those facts clearly? And in one encounter.

While composing the earlier version of this page and when I was away from the keyboard, I would run through my mind a conversation with a creationist making this claim, in which I would explain to him why his claim is wrong. I soon realized that what I was constructing was rather similar to a very popular fundamentalist proselytizing training format, the imaginary conversation (usually in cartoon form; eg, many Chick Pubs tracts, especially Big Daddy?) between you and your intended victim. Of course, when used for fundamentalist proselytizing one goal is to overwhelm and confuse your victim, making him unsure of his own position and more likely to accept your position, and another goal is to make your opponent look stupid in the hope of persuading on-lookers (that goal was explicitly admitted to by a creationist I was corresponding with).

Of course, since I am not a creationist my goal is not to deceive anyone, but rather to present the facts in the form of answers to some basic questions. My goal is to inform.

In the following, please imagine that there are three people: A creationist who uses this claim ("The Creationist"), myself ("Me"), and an interested third party (or parties, maybe even an audience) who is asking the both us this series of questions (not named, but rather emboldened).

Is the earth's rotation slowing down?
The Creationist:
Yes.

Me:
Yes.

Would that mean the earth used to rotate faster in the past?
The Creationist:
Yes.

Me:
Yes.

What effect would that have on the length of the day and the length of the year?
The Creationist:
The days would have been shorter. I'm not sure about the length of the year.

Me:
The days would have been shorter, which would cause the year to have more days in it. The actual length of the year would not change, but since the days were shorter that would mean that there would be more of those shorter days in the year.

What other effects would a more rapidly spinning earth experience?
The Creationist:
If the earth were truly ancient, then even just a million years ago it would have been spinning impossibly fast. Going back billions of years ago, the earth's spin would have been so great that the centrifugal force would pull the land masses to the equatorial regions and draw them out to a present day height of over 40 miles. The oceans would have been pushed to the poles and the overall shape of the earth changed from a sphere to a flat pancake.
(I'm not making any of that up, but rather took it directly from Wysong's description of the effects: [6] -- The Creation-Evolution Controversy, R. L. Wysong, 1981, page 164)

Me:
Not much of an effect. A million years ago the day would have been about 20 seconds shorter, which is hardly noticeable.

400 million years ago in the Devonian, a day would have about 2 hours 13 minutes shorter, in which case the year would have had about 400 of those shorter days in it. This is interesting, because coral grows a new layer every day and also displays seasonal changes over the year. Fossil coral from the Devonian indicates that there were about 400 days in the year when it grew.

If we go back about 4 billion years, then the day would have been about half as long as it is now, about 12 hours. How would that distort the shape of the earth? Well, look at Jupiter with a 10-hour day and see how much of a "flat pancake" it is.
(Source: [1] -- As the World Turns: Can Creationists Keep Time? by William M. Thwaites and Frank T. Awbrey, Creation/Evolution, Issue IX, Summer 1982, pp.18-22).

Why such a great difference between your assessments of the consequences? You had been agreeing with each other until now. How fast do you think that the earth's rotation is slowing down?
The Creationist:
The earth is slowing down by one second every 12 or 18 months. That amounts to each day getting longer by one millisecond a day.
(Various creationist sources; eg Walter Brown [3] [4], Kent Hovind [8], though here I'm presenting Hovind's claim in which he gave both those rates even though they are incompatible.)

Me:
The earth is slowing down by about two milliseconds per day every 100 years.
(Sources: USNO's Earth Orientation (EO) Department and Time Service Department, and the Slowing rotation of the Earth section of the Wikipedia article on leap seconds)

Creationist, your rate is a hundred to thousands of times too great. No wonder you get such outrageously wrong results!
(NOTE: With all their hand-waving about how fast the ancient earth is supposed to have been spinning, we don't even know what the consequences of their lower rates would be nor how much those rates would support their "flat pancake" description if at all.)

How did you two come up with your different rates of the slowing of the earth's rotation? What do you base them on?
The Creationist:
Well! Obviously the "evolutionist" got his rate from that Devonian coral and its false age from faulty radiometric dating methods, blah-blah-blah (insert typical false young-earth claims) ... .

I got my rate from how we have to add a second to the clock every 12 or 18 months because the earth had slowed down by that much. That's called a leap second, which I'm sure you've never heard of, Evolutionist!

Me:
Oh, I have indeed heard of leap seconds before and I even understand them. I have worked with leap seconds daily for two decades, since I write the software that communicates with the GPS receivers we incorporate into our products. We need to know how many leap seconds have been added since GPS time started on Sunday, 1980 Jan 06, so that we can convert GPS time, the straight count of seconds since 1980 Jan 06 started, into Coordinated Universal Time (UTC), which is what our clocks are set to. I'm afraid that it is you, Creationist, who does not understand what leap seconds are nor what they're used for.
(Source: systems knowledge gained through two decades of work experience)

No, I didn't get my rate from Devonian coral. Rather, that was simply independent confirmation of the actual rate.

Instead, I did get my rate from the International Earth Rotation and Reference Systems Service (IERS -- they kept the initials of their old name, the International Earth Rotation Service). The IERS constantly monitors and measures the earth's daily rotation. Based on their empirical observations and measurements, they determine and announce when a leap second needs to be added to the clock, to UTC.

It is the IERS which has empirically measured the rate at which the earth's rotation is slowing down as being about 1.7 milliseconds per day per century. Actually, that rate varies from about 1.4 to 2 milliseconds, so it's often just rounded up to 2 milliseconds, a kind of a worst-case upper bound.

So then, Creationist, my rate is based on direct empirical measurement of the earth's rotation, whereas yours is based on a misunderstanding of leap seconds.
(Sources: USNO's Earth Orientation (EO) Department and Time Service Department)

Well then what are leap seconds and why do we have them?
The Creationist:
All I know is what I read from a famous scientist, Doctor Kent Hovind. We have to add leap seconds because the earth is slowing down. He even gave the rate as 1000th of a second per day ([8]).

Me:
We have leap seconds for the same reason we have leap years: because the time periods we are trying to measure are not a whole number of the units we are measuring them with. That introduces a daily error in our timekeeping which accumulates with every passing day. That accumulating error eventually becomes too great and we need to correct our timekeeping by adding a leap second. That is what leap seconds do and why we have them.

BTW, sorry, but Kent Hovind is no scientist, but rather just a creationist hack whose claims are so bad they cause even other creationists to roll their eyes. None of his degrees are from an accredited school and his masters and PhD are both from the same diploma mill. Besides, just having a PhD, even a legitimate one, wouldn't make you a scientist; that would depend on what field your PhD was in. Hovind's "PhD" was not in any field of science, but rather in Religious Education, as was his Masters (his Bachelor degree was in Religion from an unaccredited Baptist college). He did teach science and math at private Christian high schools where teachers do not need to be qualified in any manner except for having the "right" religious beliefs. And he has demonstrated that he does not understand many scientific facts, such as simple physics.

Also, look at his source for that "1000th of a second per day" rate. His local newspaper, which said:

"Earth’s rotation is slowing down, June will be one second longer than normal. The earth is slowing down 1000th of a second every day."
    (Pensacola News Journal, 06 Dec 1990)
And who knows where they had gotten that from. The newspaper archives are behind a pay-wall, but I found a dissertation where the student had obtained the article and verified that it did say what Hovind claims it did. So the newspaper reporter had gotten it wrong.

Sorry for that digression, but you needed to know that you had misplaced your trust.

What's the next question?

What error are you talking about?
The Creationist:
Yeah, Evolutionist! What are you talking about?

Me:
It's very simple. Let's start by examining leap years, since you are more familiar with them and they serve the same kind of purpose as leap seconds do, hence their name.

A year is a little less than 365.25 days long. And we measure a year with a calendar, so that's our timekeeping method to measure the passage of one year. The problem is that a calendar's idea of a year is 365 whole days. The calendar knows nothing about fractions of a day. It is unable to deal with that extra quarter of a day, so every year that goes by results in the calendar being off by a quarter of a day; it accrues an error of a quarter of a day every year. So after the first year, the calendar has an error of a quarter of a day. After the second year, the calendar has an error of half a day. After the third year, the calendar has an error of three quarters of a day. After the fourth year, the calendar has an error of an entire day, which we correct by adding an extra day, 29 Feb, to the calendar. That's a leap year and that's why we have them.

The same thing applies to leap seconds. Our timekeeping method for a mean solar day is Coordinated Universal Time (UTC) which is measured with an atomic clock (actually, many atomic clocks) which defines a standard day as being 86,400 standard seconds. Since the standard second is defined according to how long a mean solar day was around 1900, that means that the earth has done a little over a century of slowing down since then. So the problem is that currently an actual day is about 2 milliseconds longer than a standard day and, like the calendar can only deal with whole days, the UTC clock only works with whole seconds and cannot deal with a fraction of a second. That means that every day that passes adds about 2 milliseconds of error to our UTC clock. There are about 548 days in an 18-month period, so in 548 days UTC can accumulate an error of about a full second. So the solution is that, when that much error will have accumulated, we correct UTC by adding a leap second. It is really that simple.

Please note that adding a leap second has nothing to do with correcting for how much the earth has slowed down during that 18-month period. If the earth were to suddenly stop slowing down and maintain a constant rate of rotation from now on, we would still need to add leap seconds periodically because an actual day would still be longer than a standard day. Consider that adding a day every leap year does not mean that the earth is slowing down in its orbit, which is a good thing since if that were happening then we would have de-orbited into the sun long ago.
(Sources: USNO's Earth Orientation (EO) Department and Time Service Department, plus systems knowledge gained from working with this stuff for two decades)

But why is the standard second based on 1900?
The Creationist:
Huh?

Me:
Well, that's a bit of a long story, which I will shorten considerably here. Basically, it wasn't until the end of the 19th century that astronomers began to suspect that the earth's rotation was slowing down and then by the 1920's they had confirmed that it was indeed happening. That was a huge problem, since most calculations in physics and astronomy include the factor of time, so if the duration of a second was constantly changing, that would throw all their calculations off which would be disastrous; they needed a time standard that would remain constant!

So the astronomers went to work using astronomical observations and orbital mechanics to solve for time, thus establishing ephemeris time which was based on the ephemeris second. Even though ephemeris time was officially established in 1952, the calculations that created it were based on observations made leading up to 1900, so the length of an ephemeris second was that of a mean solar second in 1900.

Then in the 1950's and 1960's physicists began experimenting with atomic clocks and they used the ephemeris second to calibrate their atomic clocks. Thus the atomic second, defined as a particular number of oscillations of a caesium-133 atom, was the same length as an ephemeris second. The atomic second led to the establishment of the International Second (SI Second) in 1967, which is the standard second used in UTC. The SI second is the same length as the atomic second, hence the same length as the ephemeris second, hence the same length as the mean solar second in 1900.

And that is why the standard second is based on what the mean solar second was in 1900.

So what do we conclude about this creationist claim?
The Creationist:
Uh .... .

Me:
That it is false and should not be used. Unfortunately, creationists will continue to use it. Look, it was created in 1979 and developed over the next few years. But then in the Summer of 1982 it was completely and utterly refuted ([1] -- As the World Turns: Can Creationists Keep Time? by William M. Thwaites and Frank T. Awbrey, Creation/Evolution, Issue IX, Summer 1982, pp.18-22).

And yet creationists continue to use it unabated, even when they know that it's false. In 2001 (nearly two decades after the claim was refuted), a Canadian organization, Ontario Consultants on Religious Tolerance, attempted to discuss the claim with creationists -- read their two-page article, An unsuccessful attempt to correct an error on young-earth creationist websites ([2]). They found fifteen sites that used the claim and explained the situation to the people running those sites. Most of the webmasters simply ignored them while others either refused to discuss it, insisted that the claim was correct, or else pretended to be reasonable in order to "smile you out the door." The end-result was that all of the websites continued to post the claim unchanged. That amounts to them deliberately lying.

The claim started out as an honest mistake. I've read the Popular Science article that Walter Brown lists in his bibliography and it didn't go into enough detail about leap seconds to explain them properly; it didn't confuse me because I already understood leap seconds but I can see how it could have confused a newbie like Brown. But once the claim had been found to be false, it should have been dropped. Actually, I think that Walter Brown did drop it, because I couldn't find it on his site nor in his book. But far too many other creationists do continue to use it. An author quoted in the Religious Tolerance article stated:

"I really don’t blame them for making this mistake initially. We are all entitled to a few mistakes. But this does not justify keeping this claim going for years and years. My question is, why is this claim still being made?"

The Creationist:
My head hurts!

There, I think that was a worthwhile exercise. And hopefully more clear than a few pages of prose explaining everything. Plus, if you happen to know a creationist who uses this claim, you could use it as a template for your own little tête-à-tête with him.

So to recapitulate: The creationists didn't understand what leap seconds are nor what they do, so they made the enormous mistake of assuming an extremely large rate for the earth's rotational deceleration, which in turn resulted in extremely ridiculous and utterly false conclusions. And they continue either to refuse to understand leap seconds or to lie about it in order to continue to use this false claim.


A History of the Claim

Footnote 1: It is very common for creationists to use claims made by other creationists and plagiarize that other creationist's bibliography, thus lying to their public about their sources. Since they've never seen the sources they claim and so do not know what they say, this is one reason why the first best action to refute a creationist claim is to read the source they claim.

For example, Dr. Henry Morris claimed his moon dust claim was based on a "1976" NASA document, "written well into the space age". That "1976" date was the primary point of the claim, which was meant to refute the observation that they use outdated sources. When I pulled that NASA document off the library shelf, the front cover refuted Morris' claim because it contained papers presented in 1965 and was printed in 1967. Clearly Morris had never actually seen the document that he claimed as his source. Instead, Morris' actual source was Harold Slusher, a fellow creationist, who also claimed that NASA document as his source and who, I now suspect, had also never seen that NASA document, but rather plagiarized that reference from yet another creationist.

For the full story, see my page, MOON DUST.

This claim is something of a rarity among creationist claims. Most creationist claims spread like urban legends, making it nearly impossible to trace their spread and development. Also, most creationists will just simply repeat the claim, including the claim's purported scientific source, which the creationist will claim to be his own source even though he had never seen that source 1. But in the case of this claim, most creationists cited their actual creationist source, making this claim traceable.

The most common form of the claim that we see is Kent Hovind's version. The unfortunate thing about Kent Hovind is that he avoided writing his claims, but rather would present them in his seminar videos, which were commonly available on-line. Another unfortunate thing about that is that he would update his videos periodically, so that if you referenced a claim in a video, it could easily disappear (eg, a protein comparison claim that only appeared in earlier videos, but was removed in later ones) or else be moved to a different video or a different timemark. Yet another problem with those claims only being on a video is that they would lack a bibliography, which makes researching his claim more difficult.

Fortunately, someone transcribed a set of Hovind's videos several years ago and posted that transcript on-line. I found this example of Hovind's version of the claim in a transcript at http://www.wiseoldgoat.com/papers-creation/hovind-seminar_part1b_2007.html#rotationalspeed ):

Slowing Earth

Another factor. The earth is spinning—we are turning around. How many knew that already? We are turning around. You know the earth is going a little over 1,000 miles an hour at the equator, but the earth is slowing down. It is actually slowing down 1000th of a second everyday. Pensacola News Journal, 1990, said on December 6, "Earth’s rotation is slowing down, June will be one second longer than normal. The earth is slowing down 1000th of a second every day." Astronomy magazine announced, 1992 in the June edition, "Earth’s rotation is slowing down, June is going to be one second longer than normal." We will have to have a "leap second." A leap second? Most people have heard of leap year, but lots of folks have never heard of leap second. Did you know we have a leap second about every year and a half now because the earth is slowing down? Now kids this is going to be kind of complicated so listen carefully. The earth is spinning but it is slowing down. So that means that it used to be going faster. How many can figure that out with no help? Okay several. Well, now if the earth is only 6,000 years old that is not a problem. It was probably spinning a little faster when Adam was here. Maybe they had 23 and 1/2 hours in a day. They would not notice, they did not have a watch anyway. Some of these folks want you to believe that the earth is billions of years old. Now that would make a problem. If you go back a few billion years, the earth was spinning real fast. Your days and nights would be pretty quick! Get up, go to bed! Get up, go to bed! Get up, go to bed! You would never get anything done. And a centrifugal force would have been enormous, would have flattened the earth like a pancake. The winds would have been 5,000 miles an hour from the Coriolis effect. You think the dinosaurs lived 70 million years ago? I know what happened to them? I know what happened to them... they got blown off! No they did not live 70 million years ago, folks; it simply cannot possibly be true.

Very colorful and funny. And completely wrong as you now know.

Hovind wrote another very terse version of the claim which appeared on Hovind's website in his article, Universe Is Not "Billions of Years" Old (currently renamed to Evidence from Earth of a Young Earth) -- that article's list of "young earth evidences" is also popular re-post fodder on creationist websites:

The slowing spin of the earth limits its age to less than the "billions of years" called for by the theory of evolution. (3, p. 25; 7)

3. Huse, Scott M. The Collapse of Evolution. Grand Rapids, Mich.: Baker Book House, 1983.
7. Hovind, Kent E. Creation Seminar, Parts 1-7 (most items referenced onscreen—available from Creation Science Evangelism, 29 Cummings Road, Pensacola, Fla. 32503).

This version does not provide much information, but it did provide me with a lead for tracking down the history of the claim: Scott M. Huse's version of the claim, which I will present below. This was my first lead in tracking down one line of descent of this claim. And, needless to say, I was rather pleasantly surprised with Hovind's bibliography in that article, since he broke with common creationist practice by citing his actual creationist sources rather than try to claim those creationists' purported scientific sources as his own.


But I'd rather present the versions in the reverse order in which I discovered them through research, starting with its first appearance and bringing it towards the present so that we can see it develop over time.

The earliest form of the claim that I know of was from 1979. It was cited by William M. Thwaites and Frank T. Awbrey in their classic refutation, As the World Turns: Can Creationists Keep Time? (Creation/Evolution, Issue IX, Summer 1982, pp.18-22): Evidence that Implies a Young Earth and Solar System by Walter Brown (Evidence for Creation Series, I.C.R. Midwest Center, 1979):

Atomic clocks, which have for the last twenty-two years measured the earth's spin rate to the nearest billionth of a second, have consistently found that the earth is slowing down at a rate of almost one second a year. If the earth were billions of years old, its initial spin rate would have been fantastically rapid—so rapid that major distortions in the shape of the earth would have occurred.

Then later on-line I found a PDF of a brochure that was apparently put together for a youth rally and which is dated March 1981. That brochure contained a copy of Brown's EVIDENCE THAT IMPLIES A YOUNG EARTH AND SOLAR SYSTEM which stated:

1. Atomic clocks, which have for the last 2 years measured the earth’s spin rate to the nearest billionth of a second, have consistently found that the earth is slowing down at the rate of almost one second a year. (a- c) If the earth were billions of years old, its initial spin rate would have been fantastically rapid– so rapid that major distortions in the shape of the earth would have occurred.

...

March 1981

REFERENCES
1. a) Arthur Fisher, “The Riddle of the Leap Second,” Popular Science, Vol. 202, March, 1973, pp. 110- 113, 164- 166.
b) Air Force Cambridge Research Laboratory, Earth motions and Their Effect on Air Force Systems, November 1975, p. 6.
c) Jack Fincher, “And Now, Atomic Clocks,” Readers’ Digest, Vol. III, November 1977, p. 34.

This 1981 reprint is identical except for saying "2 years" instead of "twenty-two years"; that is undoubtedly a typographical error, since 22 years prior to 1979 would place us in the late 1950's, which was indeed when time-keeping with atomic clocks started to be studied. It also provides the bibliography that Thwaites and Awbrey discuss in their own article. That Air Force publication in his bibliography supports my opinion that Walter Brown had originated the claim. He was a military officer until he retired in 1980, so he would have had easy access to military periodicals.

The next version I found was made by R. L. Wysong in his book, The Creation-Evolution Controversy (1981). Scott Huse, my lead to Wysong, had cited page 455, but it is on page 164 that we find Wysong's statement of the claim along with his bibliography:

12 -- EARTH SPIN

The rotation of the earth is gradually slowing -- losing time. A recent edition of Popular Science alluded to this in an article entitled, "The Riddle of the Leap Second." 41 The causes for this slowing are many, including gravitational drag forces exerted on the earth by the moon and sun. If the earth is billions of years old, and it has been slowing down uniformly through that time, the earth's present spin should be zero! Extrapolating backwards, the earth's spin billions of years ago would have been so great that the centrifugal force would pull the land masses to the equatorial regions and draw them out to a present day height of over 40 miles. The oceans would have been pushed to the poles and the overall shape of the earth changed from a sphere to a flat pancake. 42 But the earth is still spinning, its shape is spherical, its continents are not crowded to the equitorial regions and the oceans are not centered at the poles. What do we conclude? The earth is not billions of years old.

41. A. FISHER: "THE RIDDLE OF THE LEAP SECOND," IN POPULAR SCIENCE, 202(1973):110; SEE ALSO "TOWARDS A LONGER DAY," IN TIME, 87(FEB. 25, 1966):102.
42. THIS INFORMATION,IN PART, WAS TAKEN FROM T. BARNES' SUMMARY OF LORD KELVIN'S ARGUMENTS AGAINST A VAST AGE OF THE EARTH IN T. G. BARNES: "PHYSICS: A CHALLENGE TO 'GEOLOGIC TIME'," IN ACTS AND FACTS, 3(JULY-AUGUST 1974).

While Wysong did not cite his actual creationist source, we can see that it had been Walter Brown, since he did follow common creationist practice and cited Brown's Popular Science source as his own, though it looks as if he might have actually read it.

We also see Wysong introduce the mental image of the ancient earth spinning so fast that centrifugal force would have flattened it "to a flat pancake." This is the earliest use of this imagery that I know of -- Brown himself only spoke of "major distortions in the shape of the earth". I believe that Wysong is the source of that imagery, since he cites the ICR Impact article Physics: A Challenge to Geological Time (Impact No.16, July 1974) by Thomas G. Barnes, D.Sc. (honorary) (unfortunately, they no longer post the original article, but rather it's been redone as a web page minus the abstract and publication information):

Abstract

In contrast to the narrow specialization of present-day scientists some great physicists in the nineteenth century made significant contributions to numerous branches of science. England recognized this breadth and depth in Sir William Thomson and elevated his title to Lord Kelvin. It was Kelvin's brilliant thermodynamic analysis that gave us the absolute temperature scale that bears his name. When the Atlantic cable was laid it took the ingenious electromagnetic developments of Kelvin to make it a workable device. His best papers are to be found in a six volume set, Mathematical and Physical Papers, Lord Kelvin, (Cambridge University Press, 1911). Many of those papers employed physics to expose the errors inherent in the long-age concepts held by uniformitarian geologists.

Here is the section of that article that addresses the deceleration of the earth's rate of rotation:

III. Kelvin's First Physical Argument Against the Vast Earth-Age.

Kelvin investigated the deceleration of the earth's rate of rotation due to the energy lost through tidal currents. He showed that, if the earth had been here for 7.2 billion years, its initial rate of rotation would have been twice its present rate (the days being only 12 hours long). That would have yielded four times as much centrifugal force as at present. If, as historical geologists claim, the earth was molten in its initial state, the centrifugal force would have bulged out the mass in the equatorial region, making the earth's radius 86 kilometers greater at the equator than at the poles (the radius of the earth's sea level is presently only 21.5 kilometers greater at the equator due to the centrifugal force with its present rate of spin). Kelvin reasoned that if the earth had consolidated at that time, the land masses would have retained most of that greatly oblated shape, four times its present oblateness. As the years passed the centrifugal force would have been reduced and the oceans would have settled into two very deep basins, one at the north polar region and the other at the south polar region. The continents would in that case now be extremely high in the equatorial regions, 40 miles higher than they actually are!

Kelvin noted that, even if the earth had been molten and consolidated at some time appreciably less than a billion years ago, it would still have evidences of that centrifugal effect and its continents would run east and west around the equator rather than the present configuration of continents running more or less north and south. Today there is evidence that the earth's rate of rotation is slowing even more than the value used by Kelvin. Hence his physical argument is even stronger today. No one has ever really challenged his physics. Geologists just chose to ignore it. Nevertheless the actual configurations of the continents and seas refute "historical geology's" claim of a 4.6 billion year age for the earth. The continents stand as testimony to a recent creation of the earth, at the maximum of, not more than, say, about 500 million years old by this evidence alone.

Lord Kelvin lived and worked at the end of the 19th century, so he had to work with the knowledge and ideas of his time. For example, he used 7.2 billion years as an estimate for the age of the earth instead of our current 4.5 billion estimate which is based on radiometric dating, something that scientists of Lord Kelvin's time did not have knowledge of. And Lord Kelvin was aware that the earth's rotational rate is slowing down and he had a reasonable estimate of that deceleration rate, free of creationists' confusion about leap seconds. And he assumed that the earth's ancient shape and continental distribution would have been frozen in time (assuming that that wasn't Barnes putting words into his mouth) since he was not aware of plate tectonics nor that the earth's interior is molten.

So it was Wysong (or another unidentified creationist that Wysong got the idea from) who extended the idea of the earth's increased oblateness due to a more rapid rotation rate into the earth having been a "flat pancake" due to an impossibly high rotation rate.

Please also note that it was Wysong who left out the purported rate at which the earth's rotation is claimed to be slowing down, Walter Brown's "almost one second a year." From this point forward in this line of descent, nobody ever gives an actual rate of deceleration, but rather all they do is wave their hands. Even Hovind does not give an actual rate in his claim that is descended from this lineage; it is only in his own independent claim that he gives an actual rate -- two rates, one from an unknown source and the other, his working rate, from the local newspaper.

In turn, Wysong was a source for Scott Huse in his book, The Collapse of Evolution (1983). On page 25:

The Rotation of the Earth

The rotation of the earth is gradually slowing due to the gravitational drag forces of the sun, moon and other factors. If the earth is billions of years old, as uniformitarian geologists insist, and it has been slowing down uniformly, then its present rotation should be zero! Furthermore, if we extrapolate backward for several billion years, the centrifugal force would have been so great that the continents would have been sent to the equatorial regions and the overall shape of the earth would have been more like a flat pancake. But, as is commonly known, the shape of the earth is spherical; its continents are not confined to the equatorial regions, and it continues to rotate on its axis at approximately 1,000 mph at the equator. The obvious conclusion is that the earth is not billions of years old.

I have the 1983 edition of Huse's book, which is where I got that quote from, but I haven't located the newer 1996 edition. However, I once found a page on the Chick Publications site that quoted from the 1996 edition. Their quotation of the "The Rotation of the Earth" section was identical to the 1983 edition, which indicates to me that this claim was not changed in the new edition. Unfortunately, the link for that quote is now broken and I could not find it in a search of the site.

In turn, the 1983 edition of Scott Huse's book was the source for Hovind's version of the claim, which was the first one that I listed. The 1996 edition of Huse's book is of no direct interest in this investigation, but rather only serves as evidence that in the intervening 13 years, Huse never corrected his use of a claim that had been proven conclusively to be false.

And now you know that one particular history of the claim. Though I'm sure that there are other lines of descent that can be traced through other creationists' use of it.

 


THIS AREA UNDER CONSTRUCTION

WATCH YOUR STEP


Doing the Math

"Do the math!" - Sega 16-bit video game-set commercial, c. mid-1980's
Whenever a creationist claim deals with numbers, we need to do the math. In virtually every case, that alone is sufficient to refute the claim; eg, Kent Hovind's
solar mass loss claim.

As we read the claims I've listed, you will notice a glaring lack of math, of actual claimed rotation rates (as measured by how long a day was any given number of years ago; eg, Hovind's 23.5 hours per day 6,000 years ago, Thwaite and Awbrey's 21.75 hours per day 400 million years ago), or even of actual rates of deceleration. Instead, we see a lot of bare assertions and hand-waving, which does not leave us much to work with.

Walter Brown did give us a rate, but then only waved his hands about the consequences of that rate. In his expanded claim, Kent Hovind gave us two rates which disagree with each other, but at least he had used one of them to calculate its consequences, so at least that gives us something to work with.

I have quite a bit of work to do before I can write this section properly:

  1. One problem is that the rates are given in different units -- eg, seconds per 12 months, seconds per 18 months, milliseconds per year, milliseconds per day, milliseconds per day per century, milliseconds per year per year -- so you cannot compare the various rates to each other directly. It's not just apples and oranges, but rather fruit cocktail!

    One of the reasons I want to be able to compare the different rates directly is so that I can present more accurate assessments of how many times greater the creationist rates are than the actual rate from the IERS. Using back-of-the-envelope calculations, I've come up with a variety of ratios, so this is something that I would really like to nail down accurately.

    I need to work out procedures to convert from one set of units to the other so that I can get them all into the same units so that we can compare them to each other. And I need to verify that I am doing those conversions correctly.

  2. Another problem is applying those rates to retrodict how fast the earth should have been spinning a given number of years ago. Most of the claimed retrodictions are in terms of how long the day would have been back then -- eg, Hovind's retrodiction that the day 6,000 years ago would have been 23 and 1/2 hours long, and Thwaites and Awbrey's retrodiction that 4.6 billion years the day would have been fourteen hours long.

    What I want to do is to devise a valid way to apply these rates to make those retrodictions. The purpose is of course to compare the results of the various claimed rates. But again I want to know that I am doing it correctly.

    As a side topic, I could examine the methods used by others and how valid they are.

  3. Yet another problem I encountered playing with the back-of-the-envelope calculations for #2 was that for creationist rates I'd quickly hit a day of zero length. That is one reason why I started to question the methods being used.

  4. And finally, what's the physics of this deceleration? More specifically, how does this play out in terms of rotational kinematics? Working this problem would in turn test the validity of the various calculations that have been performed.

    That thought led me to the idea that I should also look directly at the earth's angular velocity (how many degrees per second it's spinning), translate the rates to angular deceleration (how many degrees per second per second its rotation is slowing down), and extrapolate back in time to retrodict the earth's angular velocity back then, which in turn could be used to derive a day's length at various times in the past.

This is a lot for me to think about, think through, work out, and test.

So this last section of this page will take me a while to write, but I am working on it.

 


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First uploaded on 2015 September 25.
Last updated on 2017 September 13.